Prolactin and Dexamethasone Regulate Second Messenger-Stimulated Cl⁻ Secretion in Mammary Epithelia

Figure 2

((a1) and (a2)) messenger RNA expression of prolactin receptor long form (PRLR-L) and short form (PRLR-S) in HC-11 and mouse ovary (a1) and PRLR-S-transfected HC-11 cells (a2). (a1) PRLR-L (442 bp), but not PRLR-S (332 bp), is found in HC-11 cells. PRLR-S is present in the ovary cells. (a2) HC-11 cells were transfected with PRLR-S, and both PRLR-L and PRLR-S can be detected in transfected HC-11 cells. ((b) and (c)) vector-transfected HC-11 cells (vtc) or prolactin receptor short form (PRLR-S)-transfected cells (rs) were pretreated with or without 1 μg/mL prolactin and dexamethasone (P-D) for 24 h. (b) Effect of ATP on [Ca²⁺]_i in vector-transfected or PRLR-S tranfected cells with or without prolactin and dexamethasone treatment. 100 μM ATP-evoked [Ca²⁺]_i changes are calculated as area under curve as described in Section 2. Data are mean ± SEM, and are normalized to vtc, 𝑛=4. ((c1) and (c2)) expression of mRNA of SPCA2 (c1) and TRPC3 (c2) in vector-transfected (vtc) or PRLR-S-tranfected (rs) cells ± prolactin and dexamethasone treatment. Total RNA was extracted, and realtime PCR was performed. The mRNA of ribosomal protein L19 was used as an internal control. Data represent mean ± SEM, and are normalized to vtc, 𝑛=4. *𝑃<0.05, **𝑃<0.01, and ***𝑃<0.001 versus vtc.