I. Schoenmakers et al., GROWTH-HORMONE CONCENTRATIONS IN MAMMARY SECRETIONS AND PLASMA OF THEPERIPARTURIENT BITCH AND IN PLASMA OF THE NEONATE, Journal of Reproduction and Fertility, 1997, pp. 363-367
The presence of growth hormone (GH) in mammary secretions of bitches w
as investigated in relation to plasma GH concentrations at about the t
ime of parturition and during the first weeks of lactation. Plasma GH
concentrations in neonates were measured during the first weeks of lac
tation to determine whether GH in maternal milk contributes to plasma
concentrations of GH in the neonate. Gastrointestinal uptake of GH was
studied by measurement of plasma bovine GH (bGH) concentrations after
intragastric administration of bGH. High concentrations of GH were fo
und in the mammary secretions of the bitches, particularly before part
urition and in colostrum, exceeding maternal plasma concentration up t
o 100-1000 times. GH concentrations in milk were not significantly cor
related with GH concentrations in plasma of bitches or neonates. Bovin
e GH could not be detected in neonatal plasma for 4 h after intragastr
ic administration of bGH. The presence of high concentrations of canin
e GH (cGH) in ante-partum and colostral mammary secretions is consiste
nt with the progesterone-induced mammary biosynthesis of GH. GH in mil
k is probably not absorbed from the gastrointestinal tract into the bl
ood circulation of the newborn in its intact form.