In vitro effect of alpha-MSH administration on steroidogenesis of prepubertal ovaries.
The effects of alpha-MSH on ovarian progesterone (P) and estradiol (E2) release were investigated. To this purpose, different doses of alpha-MSH were administered to prepubertal ovaries incubated under the following conditions: ten 5 min-pulses of perfusion medium (PM) plus LH at 160 ng/ml each one followed by a 25-min period of PM. The medium of the treated group contained alpha-MSH (0.1, 1, 5, or 10 microg/ml, in saline solution) and the control group saline solution. PM was assayed for P and E2 release. The area under the curve, pulse amplitude and width, and basal hormonal release were calculated for each hormone profile. With respect to P release, an increase in the areas under the curve could be observed in ovaries treated with 1, 5 and 10 microg alpha-MSH/ml. This increment generally coincided with an increase in P pulse amplitude and/or basal P release. The P pulse width was not modified. No significant variations were observed in the parameters under analysis with regard to E2 release. It is concluded that alpha-MSH administered to prepubertal ovaries could exert a physiological role through stimulation of P release.
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Laboratorio de Fisiología, Dpto. Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
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D000818:Animals; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000494:pharmacology; D010053:Ovary / Q000187:drug effects*; D011374:Progesterone / Q000096:biosynthesis; D051381:Rats; D012741:Sexual Maturation / Q000502:physiology*; D013256:Steroids / Q000096:biosynthesis*; D000521:alpha-MSH / Q000494:pharmacology*
D013256:Steroids; D011374:Progesterone; D004958:Estradiol; D000521:alpha-MSH; D007986:Luteinizing Hormone