Absence of leptin secretion compromises reproductive function and fertility in the ob/ob mouse which, when given leptin, shows a rise in serum LH levels and becomes fertile. Recently, the long and active isoform of the leptin receptor was detected in the ovary, indicating that leptin may also show direct gonad-related activity. To examine this, we studied the effect of graded doses of human leptin on estradiol (E2) and progesterone (P4) concentrations in the culture media of human granulosa-lutein cells obtained from follicular fluid of women undergoing in vitro fertilization. We also evaluated the mRNA expression of steroidogenic acute regulatory protein (StAR), aromatase, and cytochrome P450 17α (CYP17) in these cells at baseline and after exposure to leptin. Estradiol levels were significantly decreased in the media 24 hours after incubation of the cells with increasing hLeptin concentrations (10 -11 - 10 -7 mol/l). The maximal 30 % decrease in E2 production was caused by the 10 -9 mol/l hLeptin concentration; however, P4 levels in the media were not influenced by leptin. Exposure of granulosa-lutein cells to 10 -9 mol/l hLeptin did not produce any measurable changes on StAR, aromatase, or CYP17 mRNA expression. When hLeptin (10 -9 mol/l) was co-incubated with increasing concentrations of hCG (1.25 - 10 mIU/ml), IGF-II (15 - 60 ng/ml) or 1 - 6 desaminated IGF-II (desIGF-II; 15 - 60 ng/ml), it did not modify the elevation of E2 concentrations caused by each of the different stimuli. We conclude that leptin suppresses E2 secretion by human granulosa-lutein cells but does not impair the stimulatory effects of hCG and IGFs on these cells. Leptin may play a minor, but direct regulatory role on unstimulated human ovarian steroidogenesis by interfering with either the translational or post-translational steps of the baseline CYP17 and/or aromatase synthesis and/or the activation of the enzymes.
Key words:
Ovary - Leptin - Granulosa Cells - hCG - IGFs
References
-
1
Zhang Y, Proenca R, Maffei M, Barone M, Leopold L, Friedman J M.
Positional cloning of the mouse obese gene and its human homologue.
Nature.
1994;
372
425-432
-
2
Swerdloff R, Batt R, Bray G.
Reproductive hormonal function in the genetically obese (ob/ob) mouse.
Endocrinology.
1976;
98
1359-1364
-
3
Barash I A, Cheung C C, Weigle D S, Ren H, Kabigting E B, Kuijper J L, et al.
Leptin is a metabolic signal to the reproductive system.
Endocrinology.
1996;
137
3144-3147
-
4
Chehab F F, Lim M E, Lu R.
Correction of the sterility defect in homozygous obese female mice by treatment with the human recombinant leptin.
Nat Genet.
1996;
12
318-320
-
5
Cioffi J A, Shafer A W, Zupancic T J, Smith-Gbur J, Mikhail A, Platika D, et al.
Novel B219/OB receptor isoforms: possible role of leptin in hematopoiesis and reproduction.
Nat Med.
1996;
2
585-588
-
6
Mantzoros C S.
Role of leptin in reproduction.
Ann NY Acad Sci.
2000;
900
174-183
-
7
Karlsson C, Lindell K, Svensson E, Bergh C, Lind P, Billig H, et al.
Expression of functional leptin receptor in the human ovary.
J Clin Endocrinol Metab.
1997;
82
4144-4148
-
8
Zachow R, Magoffin D A.
Direct intraovarian effects of leptin: impairment of the synergistic action of insulin-like growth factor-I on follicle-stimulating hormone-dependent estradiol-17 production by rat ovarian granulosa cells.
Endocrinology.
1997;
138
847-850
-
9
Agarwal S K, Vogel K, Weitsman S R, Magoffin D A.
Leptin antagonizes the insulin-like growth factor-I augmentation of steroidogenesis in granulosa and theca cells of the human ovary.
J Clin Endocrinol Metab.
1999;
84
1072-1076
-
10
Brannian J D, Zhao Y, McElroy M.
Leptin inhibits gonadotropin-stimulated granulosa cell progesterone production by antagonizing insulin action.
Hum Reprod.
1999;
14
1445-1448
-
11
Spicer L J, Francisco C C.
The adipose obese gene product, leptin: evidence of a direct inhibitory role in ovarian function.
Endocrinology.
1997;
138
3374-3379
-
12
Giudice L C.
Insulin-like growth factors and ovarian follicular development.
Endocr Rev.
1992;
4
641-669
-
13
El Roeiy A, Chen X, Roberts V J, Shimasaki S, Ling N, LeRoith D, et al.
Expression of the genes encoding insulin-like growth factors (IGF-I and II), the IGF and insulin receptors, and IGF-binding proteins 1 - 6 and the localization of their gene products in normal and polycystic ovary syndrome ovaries.
J Clin Endocrinol Metab.
1994;
78
1488-1496
-
14
Willis D S, Mason H D, Watson H, Franks S.
Developmentally regulated responses of human granulosa cells to insulin-like growth factors (IGFs): IGF-I and IGF-II action mediated via the type-I IGF receptor.
J Clin Endocrinol Metab.
1998;
83
1256-1259
-
15
Adashi E Y, Resnik C E, Rosenfeld R G.
Insulin-like growth factor-I (IGF-I) and IGF-II hormonal action in cultured rat granulosa cells: mediation via type I but not type II IGF receptor.
Endocrinology.
1990;
126
216-222
-
16
Adashi E Y, Resnick C E, Ricciarelli E, Hurwitz A, Kokia E, Tedeschi C, et al.
Granulosa cells-derived insulin-like growth factor (IGF) binding proteins are inhibitory to IGF-I hormonal action. Evidence derived from the use of a truncated IGF-I analogue.
J Clin Invest.
1992;
90
1593-1599
-
17
Mason H D, Willis D, Hoolly J M, Cwyfan Hughes S C, Seppala M, Franks S.
Inhibitory effects of insulin-like growth factor-binding proteins on steroidogenesis by human granulosa cells in culture.
Mol Cell Endocrinol.
1992;
89
R1-4
-
18
Barreca A, Artini P G, Cesarone A, Arvigo M, Genazzani A R, Giordano G, et al.
Interrelationships between FSH and the IGF-IGFBPs system in human granulosa cells (GC) in culture.
J Endocrinol Invest.
1996;
19
35-42
-
19
Heid C A, Stevens J, Livak K J, Williams P M.
Real time quantitative PCR.
Genome Methods.
1996;
6
986-994
-
20
Hurley D M, Accili D, Stratakis C A, Karl M, Vamvakopoulos N, Rorer E, et al.
Point mutation causing a single amino acid substitution in the hormone binding domain of the glucocorticoid receptor in familial glucocorticoid resistance.
J Clin Invest.
1991;
87
680-686
-
21
Bornstein S R, Uhlmann K, Haidan A, Bornstein M E, Scherbaum W A.
Evidence for a novel peripheral action of leptin as a metabolic signal to the adrenal gland.
Diabetes.
1997;
46
1235-1238
-
22
Barkan D, Jia H, Dantes A, Bardimon L, Amsterdam A, Rubinstein M.
Leptin modulates the glucocorticoid-induced ovarian steroidogenesis.
Endocrinology.
1999;
140
1731-1738
-
23
Caprio M, Isidori A, Carta A R, Moretti C, Dufau M L, Fabbri A.
Expression of functional leptin receptors in rodent Leydig cells.
Endocrinology.
1999;
140
4939-4947
-
24
Barreca A, Artini P G, Del Monte P, Ponzani P, Pasquini P, Cariola G, et al.
In vivo and in vitro effect of growth hormone on estradiol secretion by human granulosa cells.
J Clin Endocrinol Metab.
1993;
77
61-67
-
25
Geisthovel F, Moretti-Rojas I, Asch R H, Rojas F J.
Expression of insulin-like growth factor-II (IGF-II) messenger ribonucleic acid (mRNA), but not IGF-I mRNA, in human preovulatory granulosa cells.
Hum Reprod.
1989;
4
899-902
-
26
Hernandez E R, Hurwitz A, Vera A, Pellicer A, Adashi E Y, LeRoith D, et al.
Expression of the genes encoding the insulin-like growth factors and their receptors in human ovary.
J Clin Endocrinol Metab.
1992;
74
419-425
-
27
EL Roeiy A, Chen X, Roberts V J, LeRoith D, Roberts Jr C T, Yen S SC.
Expression of the insulin-like growth factor-I (IGF-I) and IGF-II and the IGF-I, IGF-II, and insulin receptor genes and localization of the gene products in the human ovary.
J Clin Endocrinol Metab.
1993;
77
1411-1418
-
28
Kroder G, Kellerer M, Haring H U.
Effect of leptin on insulin signalling in rat 1 fibroblasts overexpressing HIR.
Exp Clin Endocrinol Diabetes.
1996;
104
66
-
29
Cohen B, Novick D, Rubinstein M.
Modulation of insulin activities by leptin.
Science.
1996;
274
1185-1188
-
30
Spicer L J, Chamberlain C S, Francisco C C.
Ovarian action of leptin: effects on insulin-like growth factor I-stimulated function of granulosa and thecal cells.
Endocrine.
2000;
12
53-59
-
31
Greisen S, Ledet T, Moller N, Joregensen J O, Christiansen J S, Petersen K, Ovesen P.
Effects of leptin in basal and FSH stimulated steroidogenesis in human granulosa luteal cells.
Acta Obstet Gynecol Scand.
2000;
79
931-935
-
32
Clement K, Vaisse C, Lahlou N, Cabrol S, Pelloux V, Cassuto D, et al.
A mutation in the human leptin receptor gene causes obesity and pituitary dysfunction.
Nature.
1998;
392
398-401
-
33
Azziz R.
Reproductive endocrinologic alterations in female asymptomatic obesity.
Fertil Steril.
1989;
52
703-725
-
34
Bussen S, Sutterlin M, Steck T.
Endocrine abnormalities during the follicular phase in women with recurrent spontaneous abortion.
Hum Reprod.
1999;
14
18-20
-
35
Imani B, Eijkemans M JC, deJong F H, Payne N N, Bouchard P, Giudice L C, et al.
Free androgen index and leptin are the most prominent endocrine predictors of ovarian response during clomiphene citrate induction of ovulation in normogonadotropic oligomenorrheic infertility.
J Clin Endocrinol Metab.
2000;
85
676-682
-
36
Bützow T L, Moilanen J M, Lehtovirta M, Tuomi T, Hovatta O, Siegberg R, et al.
Serum and follicular fluid leptin during in vitro fertilization: relationship among leptin increase, body fat mass, and reduced ovarian response.
J Clin Endocrinol Metab.
1999;
84
3135-3139
-
37
Hollmann M, Runnebaum B, Gerhard I.
Effects of weight loss on the hormonal profile in obese, infertile women.
Hum Reprod.
1996;
11
1884-1891
-
38
Carantoni M, Abbasi F, Azhar S, Schaaf P, Reaven G M.
Can changes in plasma insulin concentration explain the variability in leptin response to weight loss in obese women with normal glucose tolerance?.
J Clin Endocrinol Metab.
1999;
84
869-872
L. Ghizzoni,M.D.
University of Parma
Department of Pediatrics
14, Via Gramsci
43100 Parma
Italy
Email: E-mail:lucia.ghizzoni@unipr.it
