Tamoxifen Impairs Prepubertal Mammary Development and Alters Expression of Estrogen Receptor α (ESR1) and Progesterone Receptors (PGR)

Research has shown that prepubertal heifers experience allometric mammary growth that is influenced by the ovaries. Our purpose was to determine the role of estrogen in prepubertal mammary gland development. Sixteen Holstein calves were randomly assigned to one of two treatment groups: tamoxifen-injected (TAM) or control (CON). Calves were administered the anti-estrogen tamoxifen (0.3 mg·kg1·d1) or placebo from 28 to 120 days of age. At 120 days calves were euthanized and udders removed. Weight and DNA content of trimmed parenchymal tissue was halved (P ≤ 0.0001) in TAM compared with CON calves.
Source: Domestic Animal Endocrinology - Category: Endocrinology Authors: Source Type: research