. 2007 Feb 12;150(6):677–691. doi: 10.1038/sj.bjp.0707140

Table 2.

Affinities and potencies of relaxin family peptides for human relaxin family peptide receptors 1–4

	H1 relaxin		H2 relaxin		H3 relaxin		hINSL3		hINSL5		Porcine relaxin		Rhesus monkey relaxin		Rat relaxin
	B	F	B	F	B	F	B	F	B	F	B	F	B	F	B	F
RXFP1	8.84^a	9.10^a	9.35^b	10.60^a	7.48^d	7.72^d	5.80^d	5.40^a			8.56^b	9.09^b	9.39^b	9.76^b	7.27^b	7.70^b
			10.21^b	9.57^b	8.01^b	8.19^a	5.97^a
			10.04^d	9.42^c	8.50^a	8.82^g
			9.70^h	9.21^d	8.70^g
				10.00^h

RXFP2	8.83^a		8.30^b	7.72^b	6.97^a	>5^a	9.66^a	9.40^a			7.87^b	8.05^b	7.81^b	5.40^b	No bindng
			8.82^h	7.94^a			9.68^b	8.16^b
			9.07^d	8.04^d			9.72^d	9.24^c
			9.27^b	8.80^h			9.85^h	8.38^d
								9.80^h

RXFP3					9.38^e	9.25^a			6.30^h	Antag ^h
					9.40^h	9.38^g
					9.52^g	9.46^f
						9.52^h

RXFP4					8.84^e	8.96ⁱ			8.82^h	8.92^h
					8.92ⁱ	9.04^g
					8.96^g
					9.00^h

Abbreviations: H1, human gene 1 relaxin; H3, human gene 2 relaxin; H3, human gene 3 relaxin; INSL, insulin-like peptide; RXFP, relaxin family peptide receptor.

Competition-binding studies (B) with RXFP1 and RXFP2 were conducted with [³³P]-H2 relaxin (B33) and those with RXFP3 and RXFP4 with [¹²⁵I]-H3 relaxin. Functional studies (F) with RXFP1 and RXFP2 examined cAMP accumulation and those with RXFP3 and RXFP4 examined inhibition of forskolin stimulated cAMP accumulation.

Bathgate et al. (2006) (pK_i and pEC₅₀ (cAMP)).

Halls et al. (2005) (pK_i and pEC₅₀ (cAMP)).

Halls et al. (2006) (pEC₅₀ (cAMP)).

Sudo et al. (2003) (pIC₅₀ and pEC₅₀ (cAMP)).

Chen et al. (2005) (pIC₅₀).

Liu et al. (2003) (pEC₅₀ (cAMP inhib)).

Liu et al. (2005) (pK_i and pEC₅₀ (CRE reporter, β-gal)).

Liu et al. (2005) (pK_i and pEC₅₀ (cAMP). NB [¹²⁵I]-INSL3 for RXFP2).

ⁱ

Liu et al. (2003) (pK_i and pEC₅₀ (cAMP)).