Age-, Strain-, and Sex-Differences in the Anterior Pituitary Growth Hormone Content of Mice

Abstract

SYNOPSISThe growth, the anterior pituitary weight, and the anterior pituitary growth hormone (GH) content of C3H/He and C57BL/6 strains of mice were investigated during 12-120 days of age in the male and 30-90 days of age in the female. The pituitary GH content was measured by disc electrophoresis. The pattern of growth and the increasing rate of body weight were similar in either strain, whereas the body weight of C3H/He was always greater than that of C57BL/6 in both sexes. The whole pituitary weight increased with age until 40-60 days and became plateau thereafter in the male of both strains and the C57BL/6 female. On the other hand, the pituitary weight of the C3H/He female continued to increase until the 90th day. Although the pituitary weights were greater in C3H/He than in C57BL/6 until the 60th and 90th days of age in both sexes the pattern of its change was little different according to the strains. The variation of the relative pituitary weight per 10g body was not so remarkable with age in both strains and sexes. In both strains, the total GH content and the relative GH content per 10g body changed in a similar pattern with age, which increased until 50-60 days of age and became plateau or inclined to decrease a little after that in the male, while they continued to increase until the 90th day in the female. The total GH content in C3H/He was significantly higher than that in C57BL/6 in either sex. The relative GH content per 10g body showed no difference between strains in the male, but it was higher in C3H/He than in C57BL/6 in the female. In C3H/He, the female excelled the male not only in the total GH content but also in the GH content per observed in these areas in C57BL/6. The GH content per mg pituitary showed no noticeable variations with age, strain and sex. The significance of these findings was discussed.There is experimental evidence to show that growth hormone (OH) is essential for growth process, general metabolism, mammary gland development and lactation on which the mechanisms of GH action are not always completely clear. Further, the accerelating effect of GH on transplantable mammary tumor growth of mice has been reported (Speiser et al., 1966).The authors demonstrated that the C3H/He strain (a high mammary tumor strain) was superior to the C57BL/6 strain (a low mammary tumor strain) in growth, mammary gland development and lactational performance (Nagasawa et al., 1967a, b, c), and it was thought worthwhile to study the difference

Growth hormone function in strains of mice selected for large and small size

“…The inbred mouse strains C3H and C57BL differ in body weight at all ages, C3H being the heavier. Yanai & Nagasawa (1968) and Sinha et al (1975) both found the growth hormone content of the pituitaries to be higher in C3H than in C57BL. Baird, Nalbanov & Norton (1952) investigated two strains of Hampshire pigs that had been selected for fast and slow growth respectively.…”

Growth Hormone Cells in the Adenohypophysis Compared in Mice with High and Low Incidence of Mammary Tumors by Stereological Morphometry with Electron Microscopy

“…Thus, the greater body weight in male mice may be correlated with the greater synthesis and secretion of GH in the male pituitary compared to that of the females. The body weight of adult female in C3H/He mice is greater than that in the C57BL strain (Yanai and Nagasawa, 1968;; this study). The GH levels in the pituitary (Yanai and Nagasawa, 1968;, and in the serum ) are higher in C3H/He than in C57BL/6 mice.…”

“…The body weight of adult female in C3H/He mice is greater than that in the C57BL strain (Yanai and Nagasawa, 1968;; this study). The GH levels in the pituitary (Yanai and Nagasawa, 1968;, and in the serum ) are higher in C3H/He than in C57BL/6 mice. In this study, there was no strain difference in the population of GH cells in the adenohypophysis between C3H/He and C57BL/6 strains.…”

“…GH levels both in the pituitary (Yanai and Nagasawa, 1968; and in serum ) are higher in male mice than in the females. Thus, the greater body weight in male mice may be correlated with the greater synthesis and secretion of GH in the male pituitary compared to that of the females.…”

Identification of a variant growth hormone haplotype in mice selected for high body weight

“…This weight-selected line of mice was a subline of the Q-strain which contributed to both the FP-2 and FP-5 populations studied here. While the genetic analysis of Piddick & Falconer (1978) did not allow elucidation of the specific mechanism through which the GH endocrine unit was acting, natural variation in both circulating and pituitary GH levels has been documented in mice (Yanai & Nagasawa, 1968;Sinha et al 1974). Furthermore, variant forms of the GH molecule (Lewis, 1984), as well as variation in the processing of the GH primary transcript (DeNoto et al 1981), have been identified in rats and humans.…”