Interrelations between Growth Hormone and Sex Hormones: Physiology and Therapeutic Consequences

Abstract

Animal experiments, analysis of growth hormone (GH) secretion in the human, studies on the synergistic metabolic effects between GH and sex hormones using the stable isotope ¹⁵N, and long-term growth evaluation of patients with GH and gonadotrophin deficiency treated with testosterone and hGH show that biologically important interrelations exist between GH and sex hormones. They are operative not only at the pituitary and gonadal levels but also in peripheral tissues, where sex hormones modify the metabolic and growth-promoting effects of GH. GH is also important for an optimal androgenic effect of testosterone in development of secondary sexual characteristics. Knowledge of these interrelations is not only of physiological interest, but also of practical clinical value.

Desenvolvimento e zoometria de caprinos leiteiros jovens de diferentes grupos genéticos

“…Houve influência da idade sobre a zoometria dos animais (Tabela 2), sendo esta fase dos 60 aos 144 dias a de maior desenvolvimento corporal dos caprinos jovens, conhecida como fase pré-púbere, em que sofrem uma maior influência do hormônio do crescimento (GH, somatotropina), que regula o crescimento somático e a diferenciação (Zachmann, 1992). Não houve efeito significativo para a interação entre grupo genético e idade, na zoometria de caprinos leiteiros jovens.…”

Growth hormone: roles in female reproduction

“…' (Ogilvy-Stuart & Shalet 1992). Experimental studies suggest, however, that this statement underestimates the importance of GH in reproductive function, since GH modulates steroidogenesis, gametogenesis and gonadal differentiation as well as gonadotrophin secretion and responsiveness (Zachmann 1992). Mammary and placental roles for GH have also been proposed (Mol et al 1996, Alsat et al 1997.…”

Dissociation of increases in plasma insulin-like growth factor I and testosterone during the onset of puberty in bulls

“…In the control group, the onset of puberty in bull calves was identified by concomitant rises of plasma concentrations of testosterone and IGF-I, as described by Ronge and Blum (1989a, b) and Renaville et al (1993). It has been suggested by previous studies, particularly in humans (Kerrigan and Rogol, 1992;Zachmann, 1992;Metzger et al, 1994), that these coordinated hormonal increases are driven by growth hormone. Indeed, data from the control group in the present study suggests that the puberty-associated increase in plasma concentrations of IGF-I could result from the stimula¬ tory effect of testosterone on the somatotrophic axis, indirectly mediated via the oestrogen receptor after the aromatization of testosterone to oestradiol.…”