Hormonal profile and reproductive performance in lactation deficient (OFA hr/hr) and normal (Sprague–Dawley) female rats

Abstract

Lactation deficiency may have important consequences on infant health, particularly in populations of low socioeconomic status. The OFA hr/hr (OFA) strain of rats, derived from Sprague-Dawley (SD) rats, has deficient lactation and is a good model of lactation failure. We examined the reproductive performance and hormonal profiles in OFA and SD strains to determine the cause(s) of the lactation failure of the OFA strain. We measured hormonal (PRL, GH, gonadotropins, oxytocin, and progesterone) levels by RIA in cycling, pregnant, and lactating rats and in response to suckling. Dopaminergic metabolism was assessed by determination of mediobasal hypothalamic dopamine and dihydroxyphenylacetic acid (DOPAC) concentrations by HPLC and tyrosine hydroxylase expression by immunocytochemistry and western blot. OFA rats have normal fertility but 50% of the litters die of malnutrition on early lactation; only 6% of the mothers show normal lactation. The OFA rats showed lower circulating PRL during lactation, increased hypothalamic dopamine and DOPAC, and impaired milk ejection with decreased PRL and oxytocin response to suckling. Before parturition, PRL release and lactogenesis were normal, but dopaminergic metabolism was altered, suggesting activation of the dopaminergic system in OFA but not in SD rats. The number of arcuate and periventricular neurons expressing tyrosine hydroxylase was higher in SD rats, but hypothalamic expression of TH was higher in OFA rats at the end of pregnancy and early lactation. These results suggest that the OFA rats have impaired PRL release linked with an augmented dopaminergic tone which could be partially responsible for the lactational failure.

Impaired mammary gland T cell population during early lactation in hypoprolactinemic lactation-deficient rats

“…As previously described (Valdez et al 2007(Valdez et al , 2012, we found that OFA hr/hr rats showed lower levels of PRL compared with SD rats only during early lactation (day 2 of lactation, L2) (Fig. 1A).…”

“…The aim of this study was to explore the role of PRL in mammary T-cell population during early lactation using the lactation-deficient OFA hr/hr rats as a model (Valdez et al 2007(Valdez et al , 2012. This strain of rats has a large deletion in the desmoglein 4 gene (Bazzi et al 2004) and shows a partial blockade of the sucking stimulus resulting in low circulating PRL level only during early, and not in mid-or late lactation that leads to a severe impairment in lactation (Valdez et al 2007(Valdez et al , 2012.…”

“…This strain of rats has a large deletion in the desmoglein 4 gene (Bazzi et al 2004) and shows a partial blockade of the sucking stimulus resulting in low circulating PRL level only during early, and not in mid-or late lactation that leads to a severe impairment in lactation (Valdez et al 2007(Valdez et al , 2012. This model may provide an optimal in vivo condition for studying the association between PRL levels and T-cell homing during early lactation.…”

Traditional Unani perspective of perceived insufficient milk (Qillatul Laban) and Galactogogues: A literary research with recent studies

“…Scientific evidence overpoweringly indicates that breast feeding confers significant health benefits to mother and child and is the ideal method for feeding and nurturing infants (Mennella and Pepino, 2010) but lactation insufficiency or failure is relatively common among women (Valdez et al, 2007). Oligogalactia or Perceived Insufficient Milk (PIM) is stated as one of the reasons mentioned most often by women throughout the world for the early discontinuation of breast feeding and/or for the introduction of supplementary bottles.…”

“…Furthermore, in populations with sufficient economic resources, inadequate lactation may have minor consequences on the growth and health of the infant, because adequate substitute nourishment is available. However, in populations of low socioeconomic status, inadequate lactation can lead to severe health problems in the newborn, whereas a full lactation can assure the normal growth and development of the newborn even in situations of deficient availability of nutrients for the general population (Valdez et al, 2007). Moreover, inadequate breast feeding contributes significantly to the high prevalence of malnutrition (Mathur and Dhingra, 2009).…”