Greiner J W, Kramer R E, Colby H D
J Endocrinol. 1976 Jul;70(1):127-34. doi: 10.1677/joe.0.0700127.
Adrenal cortisol secretion is greater in female than male guinea-pigs and declines with maturation in animals of both sexes. In an attempt to determine the intra-adrenal mechanisms responsible for age and sex influences on corticosteroid output, adrenocortical enzyme activities were compared in sexually immature (3 weeks) and mature (17 weeks) animals. Adrenal mitochondrial protein concentration decreased with maturation in male and female guinea-pigs. 11beta-Hydroxylase activity in adrenal mitochondria was also lower in mature than immature guinea-pigs but greater in males than females. Neither mitochondrial cytochrome P-450 concentration nor cholesterol side-chain cleavage activity varied with age or sex. Adrenal microsomal protein concentration and 21-hydroxylase activity were similar in male and female guinea-pigs of the same age but far greater in mature than immature animals. Microsomal cytochrome P-450 concentration was unaffected by age or sex. Adrenal delta4-steroid (cortisol) hydrogenase activity increased with maturation in both male and female guinea-pigs and was higher in males than females. These observations indicate that cortisol secretion, as modified by age and sex, correlates closely with adrenal steroid reductive but not oxidative metabolism, suggesting that changes in delta4-hydrogenase activity are responsible, at least in part, for the decline in adrenal secretion during maturation in guinea-pigs.
雌性豚鼠的肾上腺皮质醇分泌量高于雄性，且两性动物的肾上腺皮质醇分泌量均会随着成熟而下降。为了确定肾上腺内部导致年龄和性别对皮质类固醇分泌产生影响的机制，研究人员比较了性未成熟（3周龄）和成熟（17周龄）豚鼠的肾上腺皮质酶活性。雄性和雌性豚鼠的肾上腺线粒体蛋白浓度均随着成熟而降低。成熟豚鼠肾上腺线粒体中的11β-羟化酶活性低于未成熟豚鼠，但雄性高于雌性。线粒体细胞色素P-450浓度和胆固醇侧链裂解活性均不随年龄或性别而变化。相同年龄的雄性和雌性豚鼠的肾上腺微粒体蛋白浓度和21-羟化酶活性相似，但成熟动物的该指标远高于未成熟动物。微粒体细胞色素P-450浓度不受年龄或性别的影响。雄性和雌性豚鼠的肾上腺δ4-类固醇（皮质醇）氢化酶活性均随着成熟而增加，且雄性高于雌性。这些观察结果表明，年龄和性别对皮质醇分泌的影响与肾上腺类固醇的还原代谢密切相关，而与氧化代谢无关，这表明δ4-氢化酶活性的变化至少在一定程度上导致了豚鼠成熟过程中肾上腺分泌的减少。
